Okay, so nothing that happened last week actually mattered. The Immortality Gate that was explained by literally less than one line of dialogue from the cartoonishly unmotivated Naismiths, the drums, the Cult of the Secret Book of Harold Saxon, and the Opposing Cult of the Secret Death Potions of Lucy Saxon, the Master Race, Donna Noble's entire life and story... None of them actually have anything to do with anything. They were just there to pad out the Christmas Special. Which, considering you're looking at nearly three hours -- which includes ten minutes each of running around in a quarry and running around a mansion with cactus people, plus an unending laser battle in space for no reason at all -- is particularly hard to justify.
But then, nothing in this one really matters all that much either. There's a lot of that back-and-forth flirting and fighting between the Doctor and the Master, but it becomes immediately clear that there's only one Master that actually matters, so the whole concept of Planet Master just sort of falls flat immediately. Then Donna reacts to her situation by exploding with light and putting some Masters to sleep, a gift from the Doctor for his BFF. Then the Master pulls it together for a few minutes so he can hang out with the Doctor and Wilf and be a normal person -- but just long enough to explain about the fucking drums one more time.
Then the Doctor gives him the full-court press as far as Companion-wooing, basically saying he wants to show the Master the whole of the universe and make out all the time. The Master is totes mcgoats about this plan, but then realizes for no real reason that the neverending drums are a big deal, or something, and he's not actually crazy. Which, though, he is. But what he doesn't know is that actually the drums are a thing that creepy Rassilon (Tim Dalton) and the Time Lords figure out inside the Timelock to make the Master be able to hear them or whatever. Also, they throw a diamond at a hologram picture of Earth that somehow lands in the yard of that stupid house of the Naismiths on the real Earth. That actually happens. The Masters run around a long time and realize that this diamond will make the Immortality Gate bring the Time Lords to Earth, so they do, and it doesn't make any goddamn sense at all and they keep saying egregious shit like, "The sound! Is tangible!" and "The star! Is a diamond! Is a star!"
Meanwhile Wilf and the Doctor run around the mansion for awhile with those obnoxious cactus people, and then go to their obnoxious cactus space ship so that Wilf can wander around like an old drunk and talk to that mysterious lady some more, while the Doctor feels a bunch of feelings. Then Wilf tries to get the Doctor to take his gun so he can kill the Master, but the Doctor is not feeling that, so then Wilf sincerely freaks out about how much he loves the Doctor, and it's moving. Right up until the fiftieth time the music starts swooning about how great Wilf is, and how real their love for each other is, and aren't Grandpas sweet, and don't you miss Grandpa at Christmas, and whatever hacky manipulative bullshit they can do for you in case having feelings is an area you're weak in.
The Master finally has to actually explain to the Doctor about the diamond and the drums and the Timelock and whatever total bullshit, and the Doctor reverses his entire belief system because the Master can't be allowed to stop his original genocide of their people. Because war made them crazy and act like Daleks, which the Master doesn't know about, because he wasn't there. Rassilon shows up with those four other Lords, thanks to the Master, and quickly turns all of Earth back to being normal people. The Master feels especially foolish at this point because he just explained how he was going to take over the Time Lord bodies too. Then he tries to be on their side, but it's hard, because all the formerly Master humans are now staring up at the sky, where Gallifrey has appeared. Which, by the way, also makes no sense because Gallifrey is shitty and on fire and Earth was supposed to be their salvation, but whatever. And no, I'm not doing a bad job of explaining it. It really is this retarded.
So the Doctor and the Master and Rassilon yell at each other for a million years. They also shoot rays of power. And the Master is still sometimes a skull-face. Meanwhile, remember that complicated nuclear device last week that served no actual purpose, where one person has to always be in there or else the other door won't open? Yeah, Wilf has wandered his ass right in there.
So big faceoff, and the Doctor saves the Master, and the Master saves the Doctor, and the mysterious Lady has no explanation at all for herself, and Donna remembers nothing about anything once again, and everybody laughs at her, and then the Time Lords go back to hell, and the Master literally just disappears with no explanation whatsoever, and then the Doctor stomps around for a year or two about how lame it is to die for somebody as old and weird as Wilf, and finally dies to save Wilf, which causes yet more screaming from the old guy. Then the Doctor groans and rolls around in bright red light for an hour or so, and then it turns out he's fine.
Except really he's not, he is regenerating. Only it's one of those regenerations that takes a half hour where he gets to visit everybody he ever met in his entire life and stare at them creepily until they cry. He gives Donna a lottery ticket, Mickey and Martha are married for the same unfortunate reason Storm's the Queen of Wakanda, he hands over Midshipman Frame's unquestionably perfect ass to Captain Jack, and finally Wilf is actually blowing him kisses at this point and saluting whenever he cries at the Doctor, which is literally constantly, and he goes to see Rose in 2005 which is sort of awesome, and then the Doctor finally, finally dies, and turns into... Jailbait. Excellent.
For rigorous teachers seized my youth,
And purged its faith, and trimm'd its fire,
Show'd me the high white star of Truth,
There bade me gaze, and there aspire.
-- The Grande Chartreuse (1855)
On once-beautiful Gallifrey there is a bottle city, fire and downed spaceships everywhere. Within, they walk across a bridge in a falling-down place, entering through a huge and lovely broken gate. Two stand guard outside the room: President Rassilon stands at the head; the mad Visionary sits at the foot. Six in total. Six for Hell.
The Visionary scribbles in the last moments of the Time War. The Doctor has disappeared, but they know his intention: "He still possesses the Moment," a Time Lady warns, "And he'll use it, to destroy Daleks and Time Lords alike." The Visionary confirms it: "Ending burning falling all of it falling the black and pitch and screaming fire, so burning..." All the prophecies agree: This is the end of the Time War. Gallifrey falls, and the Time Lords die, today. At the Doctor's hand.
"Perhaps it's time," says the Time Lady. "This is only the furthest edge of the Time War. But at its heart, millions die every second. Lost in bloodlust and insanity." The mad Visionary, the old hag, letters and symbols and time written over her body in an endless black flood, stops to listen. "With Time itself resurrecting them, to find new ways of dying, over and over again, a travesty of life." She is proud; there are tears in her throat. "Isn't it better to end it, at last?" Rassilon stands, thanks her for her opinion, and vaporizes her where she sits. His spittle and his madness. "I will not die! Do you hear me? A billion years of Time Lord history riding on our backs? I will not let this perish. I will not!"
The petty fears of empire. Another man speaks, as the Visionary scrabbles in time. "There is one part of the prophecy, my Lord. Forgive me... I'm sorry, it's rather difficult to decipher, but..." He points at the gorgeous whorls of her writing, the intertwined and timeless madness. The out-clause speaks of two survivors, two children of Gallifrey, beyond the Final Day. They are unnamed, beyond signaling their final confrontation: "The Enmity of Ages." The Time Lords assembled know what that means. The Doctor, who doctors, and the Master, who masters. And one constant word: The salvation of Gallifrey, the single point around which the Doctor revolves, the place his hearts are hidden: Earth.
The Master's problem isn't madness, not even the madness of war: it's his belief that there's a fundamental and insurmountable difference between him and anything else. The Master believes that he's alone. He is mistaken.